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Biomedical subjects

D M Yousem

Publications and source records attributed to D M Yousem.

At least 19 recordsLinked to original sources
PubMed2006

Imaging findings of a hibernoma of the neck.

Hibernoma is an uncommon benign fatty tumor that arises from the vestiges of fetal brown fat. We present a case report of a hibernoma of the neck in an asymptomatic 19-year-old girl and describe the important imaging findings. Computed tomography (CT) shows a well defined hypodense mass with septations. Magnetic resonance imaging (MRI) shows intermediate T1 and bright T2 signal of the mass and also demonstrates the characteristic marked contrast enhancement.

Adult↗
PubMed2006

Giant cell reparative granuloma of the sphenoid bone.

We present 2 patients with giant cell reparative granuloma (GCRG) of the sphenoid bone. The first patient is an 8-year-old boy with involvement of the greater wing, and the second is a 53- year-old man with a lateral pterygoid plate mass. Both patients presented with rapid expansion of lytic bone lesions, which had solid and cystic components and lacked matrix calcification. Biopsies were indeterminate for definitive diagnoses. The radiologic appearance, location, and incidence of the lesions, and the patient's age and medical history are helpful aids in narrowing the differential diagnosis of sphenoid bone lesions. However, the imaging and, occasionally, even the histologic findings may not suggest the specific diagnosis of GCRG, which must be added into the differential diagnosis of rapidly enlarging cystic bone lesions of the sphenoid bone.

Biopsy↗
PubMed2001

Imaging of the olfactory system.

The olfactory system consists of the primary olfactory nerves in the nasal cavity, the olfactory bulbs and tracts, and numerous intracranial connections and pathways. Diseases affecting the sense of smell can be located both extracranially and intracranially. Many sinonasal inflammatory and neoplastic processes may affect olfaction. Intracranially congenital, traumatic, and neurodegenerative disorders are usually to blame for olfactory dysfunction. The breadth of diseases that affect the sense of smell is astounding, yet the imaging ramifications have barely been explored.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Economic consequences of diagnostic imaging for vocal cord paralysis.

RATIONALE AND OBJECTIVES: The purpose of this retrospective study was to estimate the economic consequences of evaluating suspected vocal cord paralysis with magnetic resonance (MR) imaging and computed tomography (CT). MATERIALS AND METHODS: Reports from MR imaging (n = 30) or CT (n = 19) studies of the neck in 49 patients were retrospectively reviewed for causes of vocal cord paralysis. The patients were divided into high-suspicion (n = 20) and low-suspicion (n = 29) groups, based on the presence or absence of a clinically detectable abnormality other than vocal cord immobility. Clinic and inpatient charts were examined to determine the work-up in all cases. The Medicare Resource-based Relative Value Scale was used to estimate the costs of most procedures. RESULTS: The high-clinical-suspicion group included nine true-positive, four false-positive, seven true-negative, and no false-negative cases. Further work-up was performed in seven true-positive, three false-positive, and one true-negative cases. The total cost of immediate diagnostic work-up in these 20 patients, including MR imaging and/or CT, was $20,737 ($2,304 per true-positive case). The low-suspicion group included two true-positive, nine false-positive, 18 true-negative, and no false-negative cases. Further work-up was performed in both true-positive, four false-positive, and two true-negative cases. The total cost of immediate diagnostic work-up in these 29 patients was $21,698, (mean, $748; $10,849 per true-positive case). CONCLUSION: The average cost of finding space-occupying lesions in patients with vocal cord paralysis is more than 4.5 times higher in patients without suspicious antecedent clinical findings than in those with such a history. The benefits of obtaining negative findings and of detecting a small number of space-occupying lesions should be weighed against the costs of such examinations and of additional work-up for false-positive findings.

Algorithms↗
PubMed2001

The cerebral angiographic findings in Cogan syndrome.

SUMMARY: Cogan syndrome is an uncommon disorder of unknown etiology characterized by vestibuloauditory dysfunction and nonsyphilitic interstitial keratitis. To our knowledge, the case herein is the first report to demonstrate the cerebral angiographic findings of a patient with this syndrome.

Cerebral Angiography↗
PubMed2000

Preoperative imaging to predict orbital invasion by tumor.

BACKGROUND: Our purpose was to examine the accuracy of preoperative imaging in assessing tumor invasion of the orbit and nasolacrimal system. METHODS: Nineteen preoperative CT and 17 preoperative MR images from patients at risk for orbital invasion were retrospectively reviewed. Invasion was corroborated by pathologic and intraoperative assessment. RESULTS: Tumor adjacent to the periorbita was the most sensitive predictor of orbital invasion (90%) for both CT and MRI. Extraocular muscle involvement on MRI (100%) and orbital fat obliteration (80% MRI, 86% CT) had the highest positive predictive values of the criteria evaluated. Extraocular muscle displacement and enhancement were less accurate (<65%) predictors. No one criterion was >79% accurate in predicting orbital invasion. Six or more positive criteria predicted invasion with 67% sensitivity and 80% specificity (accuracy, 72%). CT was more accurate than MRI in seven of nine criteria. Invasion of the nasolacrimal system was predicted accurately (89%). CONCLUSIONS: Although preoperative imaging can aid in surgical planning, it should not replace intraoperative assessment in ambiguous cases of orbital invasion.

Adipose Tissue↗
PubMed2000

Clinical input into designing a PACS.

The purpose of this study was to evaluate clinical attitudes and expectations in the implementation of a neuroradiology picture archiving and communication system (PACS). A 1-page survey of expectations and clinical attitudes toward a neuroradiology mini-PACS was distributed to 49 full-time faculty members in the departments of neurosurgery, neurology, and otorhinolaryngology at an academic center. Interest in viewing soft-copy images was moderate to very high for over 89% of clinicians. All clinicians were comfortable with phone consultations with radiologists while viewing soft-copy images. Clinicians preferred retrieving images from personal computers over workstations and film libraries by 72.9%, 27.1%, and 0%, respectively. However, 38.5% of surgeons felt the need for hard copy in the operating room. Clinicians estimated that in 18.3% of cases, patients took their in-house films to outside institutions for consultations. Clinicians were enthusiastic about implementing PACS. Although acceptance of soft-copy viewing among clinicians is high, some provision for supplying hard-copy images appears to be necessary.

Attitude of Health Personnel↗
PubMed2000

Variation in parotid gland size, configuration, and anatomic relations.

PURPOSE: To examine the variation in the anatomy of parotid glands discerned by magnetic resonance imaging. METHODS: Head and neck magnetic resonance scans of 16 patients (representing 32 glands) whose studies consisted of 5 mm contiguous sections were selected at random. The T1 weighted scans were thresholded and outlined to only encompass the parotid tissue. A volumetric analysis program (ISG Technologies, Inc.) was used to compute the parotid volume in cubic millimeters. Each of the 32 glands was measured independently by two observers. RESULTS: The difference between observers averaged 4.8%. The median volume was 25,262 mm3, range 9225-54,080 mm3. In four patients there were considerable differences in the volumes of the right and left parotid glands, with variations of 9, 10, 14 and 29%. In nine patients, (18 glands) the depth from the medial edge of the gland to the spinal cord ranged from 19-32 mm. However, the maximum variation between the two sides in a single patient was 4 mm. Observations made include: (1) parotid glands extending anterior to the masseter muscle, or posterior to the posterior margin of this muscle; (2) parotid glandular tissue extending above the zygoma and the external auditory canal; (3) parotid tissue extending posteriorly to overlap the spinal cord; (4) parotid glands extending below or remaining above the angle of the mandible; and (5) wide variation of the transverse dimension of the parotid glands, with one measuring 4.8 cm. DISCUSSION: To ensure that the entire parotid is or is not in a treatment field a computerized tomography or magnetic resonance scan is necessary. If a specific portion of the gland must be in the field a volume histiogram must be available.

Dose-Response Relationship, Radiation↗
PubMed2000

Major salivary gland imaging.

The algorithm for imaging the salivary glands depends on the clinical scenario with which the patient presents to the clinician. Because of the importance of identifying small calculi in the gland or salivary duct as the cause of the symptom complex, nonenhanced computed tomography is often the best initial study for the evaluation of the painful gland. If an infiltrative neoplasm is highly suspected, nonenhanced and enhanced magnetic resonance (MR) imaging may be superior in demonstrating perineural, meningeal, and skull base invasion. Sialography is reserved for the evaluation of chronic sialadenitides unrelated to sialolithiasis. Thin-section MR techniques for MR sialography may soon replace conventional sialography.

Humans↗
PubMed2000

Posttransplantation lymphoproliferative disorder of the head and neck: imaging features in seven adults.

PURPOSE: To determine the cross-sectional imaging findings of posttransplantation lymphoproliferative disorder (PTLD) of the head and neck. MATERIALS AND METHODS: Computed tomographic (CT) scans (n = 6) and magnetic resonance (MR) images (n = 2) in seven patients with histopathologically proved PTLD of the Waldeyer (lymphoid) ring or cervical lymph nodes were retrospectively reviewed for abnormalities. RESULTS: The interval between transplantation and PTLD onset was 3.5-108 months (mean, 30 months). All patients had imaging abnormalities involving the Waldeyer ring, and focal 2.0-4. 5-cm masses were present in six patients (unilateral oropharyngeal tonsil in two, bilateral oropharyngeal tonsils in one, nasopharyngeal adenoids in three, unilateral pharyngeal tonsil and ipsilateral nasopharynx in one). In three patients, the mass was centrally low attenuating at CT or isointense to fluid at MR imaging, with enhancing solid peripheral lymphoid tissue. Three patients also had nodal findings: one with a 7-cm low-attenuating nodal mass in the right neck and two with numerous bilateral lymph nodes (mostly normal sized) in the anterior and posterior cervical lymph chains. One patient also had a small mass in the upper mediastinum. CONCLUSION: In the setting of organ transplantation, findings of masses in the Waldeyer ring or an excessive number of cervical nodes should increase the index of suspicion of PTLD.

Adenoids↗
PubMed2000

Reduced olfactory bulb volume in patients with schizophrenia.

OBJECTIVE: The authors' goal in this study was to compare the size of olfactory bulbs of patients with schizophrenia and those of healthy subjects. METHOD: Magnetic resonance imaging scans of olfactory bulbs were obtained from 26 patients with schizophrenia and 22 healthy comparison subjects. A reliable region of interest procedure was used to measure olfactory bulb volume. RESULTS: Patients exhibited 23% smaller bilateral bulb volume than comparison subjects, independent of acute clinical, demographic, or treatment measures. Bulb volume correlated with odor detection sensitivity in healthy subjects but not in patients with schizophrenia. CONCLUSIONS: Patients with schizophrenia exhibit structural olfactory deficits as well as functional olfactory deficits. The olfactory system may be a model system in which to study the neurobiology of the disorder.

Adult↗
PubMed2000

Incidence and clinical significance of frontal sinus or orbital entry during pterional (frontotemporal) craniotomy.

BACKGROUND AND PURPOSE: Frontal sinus entry, orbital entry, or both may occur during pterional craniotomy for microsurgical clipping of aneurysms. We sought to determine the incidence and clinical significance of these findings on postoperative CT scans. METHODS: Eighty-two postoperative CT scans of the head obtained from 81 patients (64 women, 17 men; age range, 25-80 years) were retrospectively reviewed over a 1-year period. These scans were reviewed independently by two blinded neuroradiologists for the presence and degree of orbit and frontal sinus entry that may have occurred during craniotomy. Clinical charts, operative notes, and discussions with the patients' neurosurgeons were reviewed to determine the clinical management and significance of these findings. RESULTS: Of the total 82 craniotomies reviewed, 77 (94%) had been performed via the pterional approach (43 right, 34 left). Twenty-three (30%) of these 77 studies revealed some evidence of penetration into the orbit or frontal sinus (orbit=65.2% [15/23]; frontal sinus=30.4% [7/23]; both=4.4% [1/23]). Only five of 16 patients with radiographic orbital penetration had evidence of involvement of intraorbital contents (ie, thickened lateral rectus, fat herniation, intraorbital air). Chart review revealed no complication or change in management. Of the seven patients with frontal sinus entry, three had mucosal exenteration and packing with antibiotic-coated gelfoam. No delayed complications (ie, persistent fever, mucocele, cerebrospinal fluid leak, air leak, or meningitis) were identified (follow-up period, 18-29 months). CONCLUSION: Frontal sinus or orbital entry is not uncommon after pterional craniotomy, but the incidence of immediate complications is rare.

Adult↗
PubMed2000

MR imaging for predicting neoplastic invasion of the cervical esophagus.

BACKGROUND AND PURPOSE: Esophageal invasion (EI) by head and neck neoplasm has important prognostic and surgical management implications. Our purpose was to determine the accuracy of MR imaging for predicting neoplastic cervical esophageal invasion. METHODS: MR scans of the neck obtained from 22 patients with periesophageal masses were retrospectively reviewed independently and by consensus by two experienced head and neck radiologists who were unaware of surgical findings. The patients were selected from clinical, radiologic, or pathologic reports suggesting EI. The following imaging criteria for EI were evaluated: effacement of periesophageal fat planes, circumferential mass, paraesophageal lymph nodes, luminal size, wall thickening, increased T2 wall signal, and wall enhancement. There were eight patients with EI and 14 patients without EI, as confirmed by surgical findings or pathologic examination. RESULTS: The consensus criteria with the best sensitivities were any wall thickening (100%), effaced fat plane (100%), and any T2 wall signal abnormality (100%). The criteria with the best specificities were circumferential mass greater than 270 (100%) or 180 degrees (93%) and focal T2 wall signal abnormality (86%). The overall kappa value for the two readers for all criteria was 0.57 (moderate agreement). CONCLUSION: A circumferential mass or focal T2 signal abnormality on the esophageal wall suggests the presence of EI. An intact fat plane, absence of wall thickening, and no T2 wall signal abnormalities imply that the esophagus is not invaded.

Adult↗
PubMed1999

Olfactory dysfunction in multiple sclerosis: relation to longitudinal changes in plaque numbers in central olfactory structures.

Scores on the University of Pennsylvania Smell Identification Test (UPSIT), as well as the numbers of MRI-determined plaques within the inferior frontal and temporal lobes, were obtained on three or four separate occasions in each of five MS patients over an 18- to 20-month period. A close association was observed, longitudinally, between the remission and exacerbation of plaque numbers and UPSIT scores, with more plaques reflecting lower UPSIT scores. These observations further support the hypothesis that olfactory loss in MS is associated with fluctuations in plaque numbers in central olfactory brain regions.

Adult↗